Stealthy packet dropping in multihop wireless sensor networks can be realized by the colluding collision attack. Colluding collision attack disrupts a packet from reaching its destination by malicious collusion at intermediate nodes. Moreover, the malicious nodes give the impression to their neighbors that they performed the legitimate forwarding action. Therefore, a legitimate node comes under suspicion. We provide a protocol called MCC to remedy the attack. MCC builds forwarding counters at each neighbor of the suspicious node and collaboratively compare the values of these counters to detect any discrepancy that could be caused by malicious packet dropping. We show through analysis and simulation that the basic local monitoring (BLM) fails to efficiently mitigate stealthy colluding collision attacks while MCC successfully mitigates them.